Aerosol filters, and particularly cigarette filters, have conventionally been produced from a great variety of fibrous materials. Of the fibrous materials employed, however, only paper and cellulose acetate tow have met with any significant commercial acceptance.
Paper filters are generally characterized by higher filtration as measured by smoke removal efficiency, but also adversely affect taste and odor of the delivered smoke stream. Moreover, their phenol selectivity is significantly lower than that available with conventional cellulose acetate tow filters. Further, paper filters are susceptible to collapse during smoking, primarily because of their tendency to absorb moisture from the tobacco smoke stream and smoker's mouth. Also, the compressibility of paper filters at a given pressure drop, i.e., resistance of the filter to air flow, is generally greater than that of conventional tow filters.
In comparison with paper filters, conventional cellulose acetate tow filters overcome all of the above disadvantages of paper filters and for this reason, are more commercially acceptable in spite of the fact that the smoke removal efficiency at a given pressure drop is relatively lower than that of paper filters.